This invention relates to fork lift trucks and particularly to an improved apparatus for automatically extending the forks of a turret stockpicker.
A typical turret stockpicker includes a power unit for propelling the vehicle down a aisle and for providing the power necessary to operate auxiliary functions such as the raising, lowering and extending of the forks. A mast on the power unit supports an operator's platform which may be raised and lowered along with the forks. The operator's platform usually includes various handles to control such as steering, braking, and movement of the forks. A load handler assembly is carried by the operator's platform and is movable transversely across the face of the platform between a home position, where any load carried by the forks is centered, and an extended limit position on the load side of the vehicle where the forks extend beyond the sides of the vehicle. A fork carriage assembly is mounted on and is vertically moveable relative to the load handler. The fork carriage assembly may be pivoted on the load handler assembly so that the forks may be pointed either to the right or to the left relative to the vehicle.
This arrangement permits the operator to place the forks at a convenient height where articles picked from shelves on the aisle may be placed. On the other hand, the operator may wish to move a box or pallet onto the fork, and in this case, the load handler assembly is moved across the face of the operator's platform toward the load, and when it reaches its extended position, the forks themselves are extended and placed under the load, the forks raised to pick up the load, and the forks are then returned to their home position and the load handler assembly is itself is moved back to its home position, thereby to center the load relative to the vehicle.
In prior art stockpickers, the operator must first move the load handler assembly from its home position to the load side of the vehicle with one control handle and then, in a separate action, extend the forks using a separate control device. Further, stockpickers typically do not include mechanical means for holding the forks in the home position so that they might drift out of the home position as the vehicle is moving down the aisle, and any movement of the fork carriage assemble with the forks out of the home position could inadvertently cause damage.